Waste water electrical power generating system with storage system and methods for use therewith

ABSTRACT

A method for selectively generating electrical power by using waste water gravity flow to generate electrical power includes attaching ends of a water flow diversion pipe to a waste water pipe. At least some of the waste water flowing by gravity through the waste water pipe is diverted into and through the diversion pipe and back into the waste water pipe. An electrical power generator is driven to generate electrical power in response to the waste water flowing through the diversion pipe. At least a portion of the electrical power generated by the at least one electrical power generator is stored and can be tapped later to supplement the output of the electrical power generator.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is related to U.S. application Ser. No.11/201,074, now U.S. Pat. No. 7,357,599, entitled, WASTE WATERELECTRICAL POWER GENERATING SYSTEM, filed on Aug. 10, 2005 and to U.S.application Ser. No. 11/842,703, now U.S. Pat. No. 7,452,160, entitled,WASTE WATER ELECTRICAL POWER GENERATING SYSTEM, filed on Aug. 21, 2007that are commonly owned.

BACKGROUND OF INVENTION

This invention relates to an improved system for generating electricalpower utilizing sewer waste liquid as the energy source for operatingturbines which, in turn, drive electrical power generators.

Conventional electrical power generating systems which use fossil andnon-fossil fuels have adverse affects on the environment. For example,electrical power-generating systems that utilize fossil fuels, such ascoal or oil, produce residual materials which pollute the atmosphere.Those pollutants result from the burning of fossil fuels to generateheat to produce steam which operates turbines that drive electricalpower-producing generators. Other electrical power-generating systemswhich utilize atomic energy to produce steam cause radiation problemsand problems in the disposal of spent, radioactive, fuel. Hydro-electricpower systems require expensive and elaborate structures, such as dams,which block rivers, and water storage ponds or lakes, which adverselyimpact the environment. Wind-operated systems, which use numerouswindmills, are not practical in many places because they require largeareas and steady winds. Also they are unsightly. In general, they arelimited to areas that have sufficient, consistent wind velocity and windstrength. Hence, efforts have been made to develop systems forgenerating electricity which eliminate or minimize the disturbance ofthe environment and the high expenses and ecological problems associatedwith conventional power-generating systems.

SUMMARY OF INVENTION

The present invention is directed to apparatus and methods of operationthat are further described in the following Brief Description of theDrawings, the Detailed Description of Preferred Embodiment, and theclaims. Other features and advantages of the present invention willbecome apparent from the following detailed description of the inventionmade with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates, in plan view, a system for divertingordinary sewage waste liquid from a sewage pipeline and utilizing thefluid to operate turbines or water wheels which, in turn, driveconventional electrical power generators in accordance with anembodiment of the present invention.

FIG. 2 schematically illustrates a modification of the inlet connectionbetween the diversion pipe or penstock from the sewage pipeline, showingschematically a sliding or lift gate which diverts the flow and thescreen system for diversion of solid materials from the entry to theturbines in accordance with an embodiment of the present invention.

FIG. 3 schematically shows, in an enlarged view, the gate at the outletend of the penstock or diversion pipe in accordance with an embodimentof the present invention.

FIG. 4 schematically illustrates a front view of a type of screen forcatching solid materials before entry into the diversion pipe orpenstock in accordance with an embodiment of the present invention.

FIG. 5 presents a block diagram representation of a waste waterelectrical power generating system that includes a storage system inaccordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

The invention herein is concerned with providing the “fuel” or energysource for operating electrical generators on a consistent basis usingthe flow of sewer waste liquid which is available in highly populatedareas. In a typical, substantial size city or suburban area, sewagewater waste discharged from homes, commercial buildings and otherstructures, is initially conveyed through feeder sewer pipes. Thesefeeder pipes ultimately drain into main or large sewer pipelines. Thesepipelines normally carry the waste liquid to treatment plants or toother locations for disposal. Commonly, all of the pipes and pipelinesare buried so that they are out of sight.

In relatively large towns and cities and densely populated suburbanareas, the discharge flow of waste sewer water is substantiallyconsistent during most of the hours of a typical day. Thus, there is afairly constant flow of liquid in large mains or interceptor sewerpipelines each day. Consequently, this invention contemplates utilizingthat waste water flow before treatment of, and before final disposal of,the sewerage liquid for operating turbines or water wheels. Thosehydraulically-powered turbines or wheels drive electrical powergenerators during times when the electrical power is needed.

The power generated by the use of waste water can be used as auxiliaryor supplemental power supply sources for established power-generatingsystems. Thus, the supplemental power is particularly useful during peaktimes when extra power is demanded from established or local electricalpower-generating installations. Peak power use times generally coincidewith peak flow in sewer lines. Alternatively, sewer waste liquid flowmay fuel a local electrical generating installation where the electricalenergy produced by such an installation is enough to meet local demands.

By utilizing the energy of the flowing sewer waste water or liquid,which is available in installed sewer pipelines, electricity can begenerated to augment or supplement a local or establishedpower-generating system without substantially affecting the localenvironment or the ecology of the local area in which the system isinstalled. And, the “fuel,” that is, the flowing sewer waste liquidwhich is otherwise totally wasted, is captured to provide a replacementfor other forms of fuel which do affect the environment and localecology.

In accordance with an embodiment of the present invention, an economicalway is presented to produce electrical energy without adverselyimpacting the environment, without utilizing fossil fuels, and withoutthe need to construct large structures such as dams or water retentionlakes, and the like. Thus, the method and apparatus involved in thepresent system for generating electrical power is based upon using awaste material, namely waste sewage water or liquid, which otherwise isunused and is normally discarded. The supply of waste sewage water isreadily available in already existing sewage pipes located in or nearpopulated areas which produce, on a daily basis, large quantities ofsewage.

Conventionally, sewage waste liquid is collected from buildings andother structures or commercial and industrial enterprises and isdischarged through underground sewer lines into larger conduits orpipes. In a relatively large, heavily populated area, local sewer pipes,in turn, feed into successively larger sewer pipelines. Ultimately theliquid is passed into one or more large main pipelines which convey theliquid to waste treatment installations or to dump locations. In mostsettled areas, the larger or main pipelines may be of a diameter thatvaries from approximately three feet up to ten feet or more. Thesepipelines, for example, may convey a flow of sewage liquid in the rangeof 8-10 feet per second for 15 to 20 hours of a day. While the volume ofliquid may vary considerably, depending upon the diameter and locationof the pipeline and the network of sewer pipes that feed liquid intolarger or main pipes, the amount of sewage liquid is considerable and isfairly consistent.

While sewage waste liquid usually includes solid materials, in manyinstallations, the solid materials are pulverized or ground up in thecourse of the flow of fluid through main pipelines. Thus, these fluidsmay be of a consistency or viscosity that is close to that of clearwater.

It is contemplated here to provide a diversion pipeline, which can bereferred to as a “penstock,” to divert from a large main or interceptorsewer pipeline at least part of the flow of liquid which travels throughthe sewer pipeline. The diverted flow of sewage liquid powershydraulically operated turbines or water wheels that are arranged in thepenstock flow. These are operatively connected to, and provide the forceneeded to, drive conventional electrical power generators. The number ofgenerators and the number of turbines or water wheels that are operatedby the flowing, diverted, waste water flow, can vary.

After the waste water or liquid passes the turbines or water wheels, itcontinues through the penstock conduit back to the sewage pipeline.Thus, the diverted waste sewage flow merges into the flow of the sewageliquid in the pipeline and continues on towards its ultimatedestination. That destination, typically, is a sewage treatment plantfor processing the sewage by removing sludge, solid particles andimpurities so that the treated water is sufficiently clean forrecycling.

The amount of electricity generated can be varied, for example, in orderto provide sufficient electrical power to augment or supplement aconventional electrical power-generating system of a particularcommunity or area. Thus, this system can be operated during peak hoursof the use of electrical power and either shut down or reduced in poweroutput during peak hours. In the alternative, a storage system can becoupled to the power generating system to store excess power duringperiods of high production and to tap this stored power during periodswhere there is low production, no production or otherwise where thedemand exceeds the then-current power output. This system may be able tomeet a community's power demands, providing a clean service ofelectrical power.

As contrasted with hydraulically-operated electrical power-generatingfacilities, the present system does not need dams or holding ponds orlakes to provide a steady supply of water to operate the system. Nordoes it affect the operation of the conventional sewage disposal systemwith which it is associated. Also, the flow of sewage water, althoughvarying at different times, is relatively consistent in volume. And thesewage normally flows throughout the year, regardless of ambient climatechanges. In a typical populated area there is enough sewage water flowto reliably produce a pre-determined amount of electrical power that maybe desired for supplementing the output of a local electricalpower-generating system.

An advantage of this invention can be to provide an electricalpower-generating system which is fueled by a stream of flowing wastesewage liquid which otherwise would have been totally discarded. Thesystem typically can be used during times of the day where heavy loadsof electricity are required in a particular area or community. The peaktimes for heavy electrical loads closely parallel the times of high flowof waste sewage in a typical community. The equipment and the method forusing sewage waste water as the energy source for the power-generatingsystem simply diverts some portion of the regular flow of sewage withoutsubstantially affecting the regular flow. Consequently, the system canbe turned on or off quickly, on short notice, for either supplying, ordiscontinuing supplying, electrical power without disrupting the sewagedisposal system.

Another advantage of this invention can be to provide an area orcommunity with a relatively inexpensive system for supplying electricalenergy without adversely impacting the environment or the local ecologyand without utilizing fossil fuels such as coal or oil. Moreover, thesystem adds relatively little by way of structure to an existing sewersystem so that the system would not be unsightly or unacceptable in manycommunities.

Yet another advantage of this invention can be to provide a relativelyeasily and inexpensively constructed arrangement for diverting, whendesired, a pre-determined amount of waste water flowing through a localsewer system, preferably through one of the main sewer lines which is oflarge diameter and has a relatively large normal flow, so as to utilizewhat would otherwise be wasted energy.

These and other advantages of this invention will become apparent uponreading the following description, of which the attached drawings form apart.

FIG. 1 schematically illustrates a system for generating electricalpower using sewage waste water flow for the operating energy inaccordance with an embodiment of the present invention. The drawingschematically illustrates a conventional sanitary sewer main pipeline 10through which liquid sewage is conveyed. Sewage may be fed into thepipeline 10 from smaller or lateral feeder pipes, not shown in thedrawing. The arrangement and construction of the sewer large or mainline and the feeder pipes are conventional.

In a conventional sewer pipeline, the pipe is sloped relative to theland so that fluid gravity flows along the length of the pipe. Sincesuch pipelines are normally relatively long, and frequently the groundcontours slope in different directions, it is customary to lay thepipeline in sections which start at a low point and slope upward to ahigh point. At the low point, the liquid in the pipe is sometimes raisedby pumping equipment to the next high point of the pipe section where itbegins its movement again.

FIG. 1 of the drawing schematically shows the lower end of a pipesection 11 connected to the upper end of the next pipe section 12 by anangled connection section 13. A conventional pump 14 lifts the flowingfluid upwardly through the connector section. Conventional pumpingequipment typically includes pump impellors which lift the fluidupwardly to the high point of the next section and simultaneously grindup or pulverize most, if not all, of the solid materials contained inthe water. Hence, over a relatively long length of sewer pipe wherethere would be a number of pumps to lift the fluid from the lower endsof sloped pipe sections to the higher ends of their adjacent pipesections, almost all, if not all, solid materials are ground up orpulverized so that the sewage flow comprises a watery liquid closelysimilar in viscosity to the flow of clear water. Such solid materials aselude the grinding are captured and temporarily removed from thepenstock as will be explained below.

A diverter pipeline 20, which may be referred to as a “penstock” orliquid conduit, has an inlet or intake end 21 connected to the pipe 10.The opposite end of the diverter pipeline 20 has an outlet 22 connectedto the pipeline 10. An inlet gate 25 is pivotally or slidably connectedat the inlet 21 and may be pivoted or slidably lifted into an open orclosed position by any conventional apparatus, which, for example, canbe conventional elongated rods having pistons arranged in hydraulicallyor pneumatically operated cylinders for moving the rods longitudinally.The rods may be connected to the gate 25 and the cylinders connected toa fixed support, so that extending and retracting the rods will swing orlift the gate into open and closed positions respectively. This is aconventional device commonly used for moving or swinging door-like orslide gate panels.

When the gate is in its closed position, as shown in the drawing, liquidflowing through the sewer line 10 bypasses the inlet gate and continueson its way through the pipeline. But, when the system is energized forproducing electrical power, the inlet gate 25 is swung or lifted intothe open position. At that point, liquid from the main sewer line isdiverted into the penstock 20. The liquid flows through the penstockthrough the outlet 22 where an outlet gate 26 is opened to discharge theflow of liquid out of the penstock. When the outlet gate is open, liquidflows back into the sewer line. The volume of liquid flow through thepenstock can be controlled by the movement of the gates into positionsthat control or regulate the amount of liquid passing into and out ofthe penstock. Turbine speed can also be controlled by adjustment ofblade pitch.

Since there is a possibility that some solids may be in the fluid thatreaches the inlet 21 of the penstock, a suitable inlet screen 27 may beprovided. Different kinds of screens are commercially available forremoving solid objects or large particles from flowing liquid. In thiscase, a suitable screen 27, as for example, may be formed of a series ofspaced-apart, parallel bars arranged into a panel. The liquid passesbetween the bars, while the solid objects are retained. Other suitablescreens may be selected by one skilled in the art from among those thatare commercially available. The screens may be pivotally or slidablyconnected within the penstock 20 interceptors or main pipeline 10, asindicated by arrow 28, so as to be swung or lifted into a position forintercepting solid materials before they enter the penstock working areawhere turbines or water wheels are located.

The filtered or screened fluid that passes through the inlet screen 27and through the penstock inlet end 21 flows through the penstock workingarea 30 and turbines. For illustration purposes, three turbines areillustrated as being in the path of the flowing liquid. These areturbine 31, at the inlet end of the working area; turbine 32, near theoutlet end of the working area, and vertically axised turbine 33, whichis horizontally arranged, to form a water wheel arrangement in themiddle of the working area. The locations and number of turbines canvary.

The turbines are rotated by the flowing liquid which is indicated byarrows 34. When activated the turbines rotate their respective driveshafts 31 a, 32 a, and 33 a. The drive shafts are connected toconventional electrical power generators 31 b, 32 b, and 33 b.

The generators, in turn, are connected by electrical lines 36 c, 32 cand 33 c to a conventional power distribution control system 36, whichis schematically illustrated. The distribution system is connected byelectrical lines 37 to power transmission lines which are schematicallyillustrated by tower-like symbols 38.

The sizes and capacities of the turbines, generators and distributionsystem may vary, depending upon the generating capacity designed intothe system. Commercially available equipment can be used for theseitems. All of these items may be contained within a housing 40, of asize and shape to provide protection for the equipment and for minimaldisturbance of the local area in which the equipment is positioned.

By way of examples of the operating capacities of the equipment, it iscontemplated that a sanitary sewer main line of about 102″ in diameter,with a liquid flow of about 8-10 feet per second, can generate in theneighborhood of 6.8 megawatts per hour of electrical power from a singleconventional generator. The number of generators may be increased. Forexample, 10 generators connected to corresponding turbines located inthe path of the penstock flow, might then produce about 60-70 megawattsper hour. That is approximately enough power for about 40,000 dwellinghomes. This is based upon an anticipated average of about 25-30 kilowatthours per day per house. Hence, a substantial amount of supplemental orauxiliary electrical power is provided. This generated electrical powercan either entirely power a community or can be utilized during peaktimes, or such other times when outside electrical power is needed tosupplement the output of a usual, electrical power-generatinginstallation.

Since it is possible that some solid objects may be carried along in theflow or that some of the particles of ground-up objects are large enoughto damage the turbine blades, the inlet screen 27 blocks the solids fromtraveling from the sewage pipe into the intake of the penstock. Thesesolids can be caught by the screen and dumped into a catch basin 50located above the screen and beneath an opening, that the pipe 10, thatis normally closed by a hatch panel 51. As shown schematically by arrows52, the solid materials are then carried back into the main sewage line,through a chute 53, downstream of the penstock intake end oralternatively may be otherwise removed from the catch basin.

FIGS. 2 and 4 illustrate a modification which includes slide orlift-type gates for controlling the flow of the sewage water into andthrough the penstock. Referring to these figures, the penstock ordiversion pipe 20 is connected to the main sewage pipeline 10 at 21. Agate 60 is located in the main pipeline and has an opening 61 throughwhich the sewage may pass. The opening, or the amount that the openingis uncovered, is controlled by a slide gate 62 which is moved to cover,partially uncover, or completely uncover the opening 61 by means of ahydraulic or pneumatic system including a piston rod 63 and a cylinder64 which moves the piston rod endwise. Similarly, gate 60 a may bepositioned at the juncture 21 between the penstock and the sewage pipe.Optionally, both gates 60 and 60 a may be installed. Gate 60 a mayinclude an opening 61 a through which fluid is diverted into thepenstock. The opening is covered by a slide or lift gate 62 a which ismoved by a piston rod 63 a powered by a cylinder 64 a to uncover theopening.

Once the sewage enters into the penstock, it passes through a screen 68,which may be formed of parallel bars or other suitable screeningmaterial for catching sold particles. The particles may be dropped orflushed into a catch basin 69 and then flushed through a connecting pipe70 back to the main sewage line downstream of the connection 21 betweenthe penstock and the sewer line. Arrows 65 illustrate the flow of thesewage through the main line and dotted arrows 67 indicate the flow ofthe diverted liquid through the penstock to the turbines (not shown).

After the fluid passes and powers the turbines or water wheels, FIG. 3schematically illustrates the return of the diverted fluid through aslide gate 76 connected to suitable piston rods 77 that are powered byhydraulic or pneumatic cylinders 78. Thus, the connection of thepenstock to the main sewer line at 22 may be opened, partially opened,or completely opened, to control the outlet of fluid from the penstock.

FIGS. 2 and 3 are plan views, i.e., looking down, on the inlet andoutlet portions, respectively, of the penstock. Thus, the slide gatesmay be moveable sideways or up and down, depending upon the desireddesign of the installation.

In water flows which are of high pressure or relatively high pressure,the use of slide gates to control the flow of water is common and,therefore, here, as in other water-controlled installations, the sizesand shapes of the openings and the gates and the equipment for movingthe slide gates is known and those skilled in the art would be expectedto design the size and shape and power required to operate the gates inaccordance with the amount of flow anticipated.

To summarize, large diameter, such as main interceptor sewer linestypically carry large amounts of sewage liquid. As the sewage liquidflows through the line, it is periodically passed through pumpingstations, to raise the level of the flow in order to implement downhillgravity flow. At the same time, the solid materials in the liquid arepulverized, leaving little, if any, solid objects. Then, when desired, aportion of that watery liquid flow is diverted into the penstock whereit operates turbines. The term “turbines” includes water wheels or anyother hydraulically-operated equipment used in electricalpower-generating systems.

The turbines drive electrical power generators. The generatedelectricity is transmitted to power transmission equipment fortransmission into the established power distribution system of theparticular area involved. Hence, the fuel needed to generate theelectrical power is provided by the waste water which otherwise wouldhave been unused and discarded. As a result, the system eliminates orreduces the need for fossil fuels, burning or steam-generationequipment, atomic energy powered equipment and water-holding equipmentsuch as dams, water holding ponds, and the like. Hence, the system hasminimal impact, if any, upon the environment or upon the sanitary sewerdistribution or treatment systems.

FIG. 5 presents a block diagram representation of a waste waterelectrical power generating system that includes a storage system inaccordance with an embodiment of the present invention. In particular,waste water power generation system 100, such as any of the electricalpower generating systems described in conjunction with FIGS. 1-4, iscoupled to power distribution system 104, such as power transmissionsystem coupled to transmission line 37, a home, office or other entitythat distributes and/or consumes the electrical power generated by powergeneration system 100. Storage system 102 includes one or more energystorage devices that store electrical energy produced by powergeneration system 100 during periods of energy production and thatsupplement the supply electrical power to power distribution system 104,either during periods of peak demand by power distribution system 104 orduring periods of reduced production from the power generation system100.

In an embodiment of the present invention, storage system 102 stabilizesor otherwise evens the flow of electrical power from power generationsystem 100, by storing excess power generated during times of peakproduction, and by supplementing the electrical power output of powergeneration system 100, either in total or in part, by tapping into theelectrical power stored in storage system 102. For instance, storagesystem 102 can include one or more batteries, capacitors or otherelectrical energy storage devices that store electrical power producedby power generation system 100 during period of peak production, such asduring peak waste water flow.

In this mode of operation, a power distribution control system of powergeneration system 100, such as power distribution control system 36, orother power distribution control system implemented as part of powergeneration system 100, storage system 102, power distribution system 104or as a stand alone unit, distributes a portion of the electrical powergenerated by power generation system 100 to power distribution system104 while distributing the excess electrical power generated by powergeneration system 100 to storage system 102. Alternatively the storagesystem 102 can include one or more other energy storage devices, such asa spring, flywheel, pressure accumulator, or other device that convertsexcess electrical power from power generation system 100 into analternative form of energy. The excess power stored in storage system102 can be tapped to supplement the output of power generation system100 during periods of reduced power production or in other circumstanceswhen the demand for electrical power exceeds the then-current productionby the power generating system 100.

For example, excess electrical energy can drive a pump that pumps water,such as waste water or other water from a supplemental source, into awater tower, converting the excess electrical power into potentialenergy of the water. When the storage system 102 needs to tap thisenergy, the water can be drained from the tower and the flow of thewater and diverted to the penstock or diversion pipe of the powergeneration system 100 to drive the turbines or waterwheels of thissystem to generate additional electrical power. Alternatively water fromthe water tower can be diverted to drive turbines or waterwheels of thestorage system 100 to generate the supplemental electricity required bypower distribution system 104.

In a further mode of operation, storage system 102 and power generationsystem 100 can operate to store excess electrical power during periodsof low demand of power distribution system 104, such as overnight orother periods of reduced demand. Power stored by storage system 102 canbe tapped to meet periods where the electrical power output of powergeneration system 100 would otherwise be insufficient to meet the powerdemands of power distribution system 104.

While storage system 102 has been described in terms of storing excesselectrical power of power generation system 100, mechanical powergenerated by the turbine or waterwheel shafts could likewise drivemechanical energy storage devices such as a springs, flywheels and/orother storage devices that convert and store at least a portion of therotational energy of the shaft to a potential energy that can be tappedto drive the turbines or waterwheels when required. In this fashion, thestored rotational energy of these storage devices could be tapped, suchas during periods of low waste water flow, to supplement the rotationalenergy of the turbine or waterwheel.

The foregoing describes a preferred embodiment of the system and methodof operation that includes several optional functions and features.Thus, having fully described at least one operative embodiment, itshould be understood that the invention herein may be further developedwithin the scope of the following claims.

1. A waste water electrical power generating system for installation inassociation with a waste water pipeline through which waste water flowsby gravity, the waste water electrical power generating systemcomprising: a diversion pipe line having an inlet end connected to thewaste water pipeline for receiving waste water from the waste waterpipeline by gravity flow and having a discharge end connected to thewaste water pipeline for discharging waste water back into the wastewater pipeline; and at least one electrical power generator whichgenerates electrical power in response to the waste water flow throughthe diversion pipe; a storage system, coupled to the at least one powergenerator, that stores at least a portion of the electrical powergenerated by the at least one electrical power generator; wherein wastewater flowing through the waste water pipeline by gravity may beselectively diverted through the diversion pipe inlet to flow throughthe diversion pipe and then back into the waste water pipeline throughthe discharge connection for operating the electrical power generatorwhen desired.
 2. The waste water electrical power generating system ofclaim 1 further comprising: at least one turbine coupled to drive the atleast one electrical power generator in response to the waste water flowthrough the diversion pipe.
 3. The waste water electrical powergenerating system of claim 1 further comprising: at least one waterwheel coupled to drive the at least one electrical power generator inresponse to the waste water flow through the diversion pipe.
 4. Thewaste water electrical power generating system of claim 1 wherein thestorage system is coupled to tap the stored electrical power and tosupplement the electrical power generated by the at least one electricalpower generator.
 5. The waste water electrical power generating systemof claim 1 wherein the electrical power generator and the storage systemare coupled to an electrical power transmission system for providing theelectrical power to the electrical power transmission system and thestorage system is coupled to tap the stored electrical power and tosupplement the electrical power generated by the at least one electricalpower generator during a period of high demand of the electrical powertransmission system.
 6. The waste water electrical power generatingsystem of claim 1 wherein the electrical power generator and the storagesystem are coupled to an electrical power transmission system forproviding the electrical power to the electrical power transmissionsystem and the storage system is coupled to store at least a portion ofthe electrical power generated by the at least one electrical powergenerator during a period of low demand of the electrical powertransmission system.
 7. A method for selectively generating electricalpower by using waste water gravity flow to generate electrical power,the method comprising: attaching ends of a water flow diversion pipe toa waste water pipe; diverting at least some of the waste water flowingby gravity through the waste water pipe into and through the diversionpipe and back into the waste water pipe; driving an electrical powergenerator for generating electrical power in response to the waste waterflowing through the diversion pipe; and storing at least a portion ofthe electrical power generated by the at least one electrical powergenerator.
 8. The method of claim 7 further comprising: tapping thestored electrical power to supplement the electrical power generated bythe electrical power generator.